Hi,

I'm quite new to Houdini so have been going through a lot of tutorials, so what I've learned is quite a mishmash of different projects. I'm trying to put into practice what I've learned so far and combine rigidbodies and vellum cloth to create a simulation of a buckle with two straps attached. At the moment I just want the buckle to be suspended by the straps, but it just seems to fall forever. Could anyone point me in the direction of what's best to do?

Thanks, I've attached my project file below

So the rbd solver and the vellum solver use two different solving methods. As a result they don't really act on one another.

The buckle object isn't included in your scene, so I can't play it down, but the way your project is wired, what is happening is that the buckle is being calculated on its own by the rigid body solver, which has no idea that the straps exist, so it just falls forever. Then the resulting simulation is being fed into the vellum simulation as an animating collider object (but nolonger simulated). Hence the problem. The buckle doesn't know the straps are there until it is too late...

Prior to v19 there were some convoluted ways to hack some kinds of interactions. If you Google "vellum rigid bodies" you'll find some examples. Usually they involved jacking up the stiffness to some ungodly level and adding additional constraints. But they were generally buggy and limited.

But with 19, there is now a shape match constraint, which allows you to use vellum as a unified solver with the "shape matched" objects behaving like rigid bodies. It's not perfect, but works in a pinch.